Mix the white wine with the water, the white wine vinegar, the sugar, the salt and the thyme. Bring this to a boil.
Meanwhile cut the pearl onions and half and clean them. On some I also had to trim the top and bottom, but this is up to your preference.
Once the sweet and sour is boiling add the cleaned onions and let it simmer for another minute.
After the minute transfer both the onions and hot liquid into a preserving jar and close the lid. Let it cool down and then let the flavors infuse for at least 24 hours in your fridge. This will result in a fresh and sweet pearl onion with a lovely little bite.